African Clawless Otter
Encyclopedia
The African clawless otter (Aonyx capensis), also known as the cape clawless otter or groot otter, is the second largest freshwater species of otter
. African clawless otters are found near permanent bodies of water in savannah and lowland forest areas. They range through most of sub-Saharan Africa
, except for the Congo basin
and arid areas.
They are characterized by partly webbed and clawless feet, from which their name is derived.
) and of the order Carnivora
. The earliest known species of otter, Potamotherium
valetoni, occurred in the upper Oligocene of Europe: A. capensis first appears in the fossil record during the Pleistocene
. Aonyx is closely related to the extinct giant Sardinia
n otter, Megalenhydris
.
lists six subspecies of Aonyx capensis:
However some authorities consider the Congo/Cameroon clawless otter
to be a separate species (A. congicus). Under this view, only the first three of the above list would be subspecies of A.capensis.
, the African clawless otter is often twice as massive as that relatively diminutive mustelid.
, the otters live in areas surrounding permanent bodies of water, usually surrounded by some form of foliage. Logs, branches, and loose foliage greatly appeal to the otter as this provides shelter, shade and great rolling opportunities. Slow and rather clumsy on land, they build burrows in banks near water, allowing for easier food access and a quick escape from predators. In the False Bay area of the Cape Peninsula they have been observed scavenging along beaches and rocks and hunting in shallow surf for mullet. They are mainly nocturnal in urban areas and lie up during the day in quiet bushy areas.
Awkward on land but acrobats in the water, these animals spend their days swimming and catching food. They return to underground burrows for safety, cooling or a nice rub down using grasses and leaves. Mainly aquatic creatures, their tails are used for locomotion and propel them through the water. They are also used for balance when walking or sitting upright.
and fish eagles
. If threatened, a high pitched scream is emitted to warn neighboring otters and confuse a predator.
, is a hiking trail in South Africa
named after the African clawless otter, which is found in this area. Otters along the trail are protected, as the trail falls within the Tsitsikamma National Park
.
Otter
The Otters are twelve species of semi-aquatic mammals which feed on fish and shellfish, and also other invertebrates, amphibians, birds and small mammals....
. African clawless otters are found near permanent bodies of water in savannah and lowland forest areas. They range through most of sub-Saharan Africa
Sub-Saharan Africa
Sub-Saharan Africa as a geographical term refers to the area of the African continent which lies south of the Sahara. A political definition of Sub-Saharan Africa, instead, covers all African countries which are fully or partially located south of the Sahara...
, except for the Congo basin
Congo River
The Congo River is a river in Africa, and is the deepest river in the world, with measured depths in excess of . It is the second largest river in the world by volume of water discharged, though it has only one-fifth the volume of the world's largest river, the Amazon...
and arid areas.
They are characterized by partly webbed and clawless feet, from which their name is derived.
Taxonomy
Aonyx capensis is a member of the weasel family (MustelidaeMustelidae
Mustelidae , commonly referred to as the weasel family, are a family of carnivorous mammals. Mustelids are diverse and the largest family in the order Carnivora, at least partly because in the past it has been a catch-all category for many early or poorly differentiated taxa...
) and of the order Carnivora
Carnivora
The diverse order Carnivora |Latin]] carō "flesh", + vorāre "to devour") includes over 260 species of placental mammals. Its members are formally referred to as carnivorans, while the word "carnivore" can refer to any meat-eating animal...
. The earliest known species of otter, Potamotherium
Potamotherium
Potamotherium an extinct genus from the Miocene period, which has been assigned both to the mustelids and to the pinnipeds....
valetoni, occurred in the upper Oligocene of Europe: A. capensis first appears in the fossil record during the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
. Aonyx is closely related to the extinct giant Sardinia
Sardinia
Sardinia is the second-largest island in the Mediterranean Sea . It is an autonomous region of Italy, and the nearest land masses are the French island of Corsica, the Italian Peninsula, Sicily, Tunisia and the Spanish Balearic Islands.The name Sardinia is from the pre-Roman noun *sard[],...
n otter, Megalenhydris
Megalenhydris
Megalenhydris barbaricina is a Late Pleistocene giant otter from Sardinia. It is known from a single skeleton, discovered in the Grotta di Ispinigoli near Dorgali, and was described in 1987. It is one of three extinct otter species from Sardinia. The others are Algarolutra majori and Sardolutra...
.
Subspecies
Mammal Species of the WorldMammal Species of the World
Mammal Species of the World, now in its 3rd edition, is a standard reference work in zoology giving descriptions and bibliographic data for the known species of mammals.An updated Third Edition of Mammal Species of the World was published late in 2005:...
lists six subspecies of Aonyx capensis:
- Aonyx capensis capensis (Schinz, 1821)
- Aonyx capensis hindei (Thomas, 1905)
- Aonyx capensis meneleki (Thomas, 1903)
- Aonyx capensis congicaCameroon Clawless OtterThe Cameroon Clawless Otter is a subspecies of the African Clawless Otter in the Mustelidae family. It is found in Cameroon, Republic of the Congo, Democratic Republic of the Congo, Gabon, and possibly Angola, Burundi, Central African Republic, Equatorial Guinea, Nigeria, Rwanda, or Uganda...
(sic) (Lönnberg, 1910) - Aonyx capensis microdon (Pohle, 1920)
- Aonyx capensis philippsi (Hinton, 1921)
However some authorities consider the Congo/Cameroon clawless otter
Cameroon Clawless Otter
The Cameroon Clawless Otter is a subspecies of the African Clawless Otter in the Mustelidae family. It is found in Cameroon, Republic of the Congo, Democratic Republic of the Congo, Gabon, and possibly Angola, Burundi, Central African Republic, Equatorial Guinea, Nigeria, Rwanda, or Uganda...
to be a separate species (A. congicus). Under this view, only the first three of the above list would be subspecies of A.capensis.
Description
African clawless otters have thick, smooth fur with an almost silky underbelly. Chestnut in color, they are characterized by white facial markings that extend downward towards their throat and chest area. Paws are partially webbed with five fingers, and no opposable thumbs. All lack claws except for digits 2, 3, and 4 of the hind feet. Their large skull is broad and flat, with relatively small orbits and a short rostrum. Molars are large and flat, used for crushing of prey. Male otters are slightly larger than females on average. Adults are 113-163 cm (45-64 in) in length, including a tail that comprised about a third of the length. Weight can can range from 10-36 kg (22-80 lbs), most otters averaging between 12 and 21 kg (26-46 lbs). Despite being closely related to the Oriental small-clawed otterOriental Small-clawed Otter
The oriental small-clawed otter , also known as Asian small-clawed otter, is the smallest otter species in the world, weighing less than 5 kg. It lives in mangrove swamps and freshwater wetlands of Bangladesh, Burma, India, southern China, Taiwan, Laos, Malaysia, Indonesia, the Philippines,...
, the African clawless otter is often twice as massive as that relatively diminutive mustelid.
Habitat
African clawless otters can be found anywhere from open coastal plains, to semiarid regions, to densely forested areas. Surviving mostly in southern AfricaAfrica
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, the otters live in areas surrounding permanent bodies of water, usually surrounded by some form of foliage. Logs, branches, and loose foliage greatly appeal to the otter as this provides shelter, shade and great rolling opportunities. Slow and rather clumsy on land, they build burrows in banks near water, allowing for easier food access and a quick escape from predators. In the False Bay area of the Cape Peninsula they have been observed scavenging along beaches and rocks and hunting in shallow surf for mullet. They are mainly nocturnal in urban areas and lie up during the day in quiet bushy areas.
Reproduction
Females give birth to litters containing 2-5 young around early spring. Mating takes place in short periods throughout the rainy season in December. Afterwards, both male and females go their separate ways and return to a solitary life once more. Young are raised solely by the females. Gestation lasts around 2 months (63 days). Weaning takes place between 45–60 days, with the young reaching full maturity around one year of age.Diet
The diet of Aonyx capensis primarily includes water dwelling animals such as crabs, fish, frogs, and worms. They dive after prey to catch it, then swim to shore again where they eat. Their hands come in handy as searching devices and are great tools for digging on the muddy bottoms of ponds and rivers, picking up rocks and looking under logs. Extremely sensitive whiskers (vibrissae) are used as sensors in the water to pick up the movements of potential prey.Behavior
Though mostly solitary animals, African clawless otters will live in neighboring territories of family groups of up to 5 individuals. Each still having their own range within that territory, they mostly keep to themselves unless seeking a mate. Territories are marked using a pair of anal glands which secrete a particular scent. Each otter is very territorial over its particular range.Awkward on land but acrobats in the water, these animals spend their days swimming and catching food. They return to underground burrows for safety, cooling or a nice rub down using grasses and leaves. Mainly aquatic creatures, their tails are used for locomotion and propel them through the water. They are also used for balance when walking or sitting upright.
Predation
Quick in the water and burrowing on land, A. capensis doesn’t have many predators. Their greatest threat comes from the python, which will often lay in wait near or in the water. Other predators would include the crocodileCrocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...
and fish eagles
African Fish Eagle
The African Fish Eagle or – to distinguish it from the true fish eagles , the African Sea Eagle – is a large species of eagle that is found throughout sub-Saharan Africa wherever large bodies of open water occur that have an abundant food supply. As a result of its large range, it is known in many...
. If threatened, a high pitched scream is emitted to warn neighboring otters and confuse a predator.
Thermoregulation
Living in Africa, circumstances can become very hot. Staying cool means spending time in the water, and also using burrows as a way to escape the highest temperatures of the day. African clawless otters use their watery surroundings as a way of cooling down. During the day, they are usually found underground in their burrows to escape the highest temperatures. To stay warm on the other hand, the otters depend solely on their thick fur. Guard hairs cover the body acting as insulate. Since the otter lacks an insulating layer of body fat, their only means of warmth is provided by their thick coats of fur.Economic Impact
The biggest threat imposed on African clawless otters comes from humans. Aonyx will often forage in man-made fisheries and may be hunted or become entangled in nets. Over-fishing by humans may reduce the food supply available to otters. They are sometimes hunted for their thick soft pelts, which humans use in forms of clothing. In forested areas, logging may be a major threat since erosion leads to greatly increased turbidity in rivers which can in turn greatly reduce the populations of fish on which the otters depend. This may well be a far greater threat to otters than hunting.Conservation
Often hunted for their soft pelts, or killed by local competitive fishermen. The Otter TrailOtter Trail
The Otter Trail is a hiking trail along the Garden Route coast of South Africa and is named for the Cape Clawless Otter which occurs in this region. This trail is widely regarded as one of the finest in the world and stretches from Storms River Mouth in the east to Nature's Valley in the west, is...
, is a hiking trail in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
named after the African clawless otter, which is found in this area. Otters along the trail are protected, as the trail falls within the Tsitsikamma National Park
Tsitsikamma National Park
The Tsitsikamma National Park is a coastal reserve on the Garden Route in South Africa. It is well known for indigenous forests, dramatic coastline, and the Otter Trail. On 6 March 2009 it was amalgamated with the Wilderness National Park and various other areas of land to form the Garden Route...
.